Molten metal shaft coupling system

Abstract

A molten metal pump shaft coupling system for use in the coupling or connection of elongated shafts to other components and equipment, and for the disconnection thereof. A coupling with internal discontinuous threads may be coupled with an externally threaded shaft, with either continuous or discontinuous threads. Aspects of the invention include multiple external threads which may be pitched to accomplish a quicker and more efficient disconnect system. Furthermore, a shaft removal system is provided which provides two points of contact to assist in rotating a broken shaft end out of a coupling.

1. A coupling system for use in molten metal processing in attaching a shaft to a drive system, the coupling system comprising:
 a coupling with a first end configured for operational attachment to a drive system, and a second end with an open inner cavity configured to receive an elongated shaft, the inner cavity including a plurality of discontinuous threads patterned to rotationally engage external threads on the elongated shaft; 
 a shaft with an elongated body having a first end and a second end, the first end being configured to be coupled to a drive and the second configured for coupling to a molten metal processing component; 
 wherein the first end includes a plurality of parallel threads configured for engagement with a plurality of corresponding discontinuous threads, and further wherein the plurality of parallel threads each extend less than one revolution around the shaft. 
 
   
   
     2. A coupling system as recited in  claim 1 , and further wherein the plurality of parallel threads on the shaft each extend less than one-half of a revolution around the shaft. 
   
   
     3. A coupling system as recited in  claim 1 , and further wherein the plurality of parallel threads each extend less than one-third of a revolution around the shaft. 
   
   
     4. A coupling system as recited in  claim 1 , and wherein the shaft further includes:
 a first shaft aperture extending longitudinally through at least a portion of the shaft; 
 a second shaft aperture extending longitudinally through at least a portion of the shaft and offset a transverse distance from the first shaft aperture; and 
 wherein the first shaft aperture and the second shaft aperture are each configured to receive part of a shaft removal tool. 
 
   
   
     5. A method for coupling a shaft utilized in a molten metal processing system to a drive system, comprising the following:
 machining at least one external thread into a first end of the shaft; 
 providing a coupling with an inner cavity, the inner cavity including a plurality of discontinuous thread sections configured to threadingly engage the at least one external thread in the first end of the shaft; 
 aligning the coupling with an entrance of the at least one external thread; and 
 rotating the at least one external thread into the coupling until securely attached. 
 
   
   
     6. A method for coupling a shaft utilized in a molten metal processing system to a drive system as recited in  claim 5 , and further wherein the at least one external thread machined into the first end of the shaft consists of a plurality of parallel threads about the shaft. 
   
   
     7. A method for coupling a shaft utilized in a molten metal processing system to a drive system as recited in  claim 5 , and further wherein the shaft is rotated less than one revolution before it effectively attaches the shaft to the coupling. 
   
   
     8. A method for coupling a shaft utilized in a molten metal processing system to a drive system as recited in  claim 5 , and further wherein the shaft is rotated less than one-third of a revolution before it effectively attaches the shaft to the coupling. 
   
   
     9. A coupling for use in molten metal processing, comprising:
 a first end configured for operational attachment to a drive system; 
 a second end with an open inner cavity configured to receive an elongated shaft, the inner cavity including a plurality of discontinuous threads patterned to rotationally engage external threads on the elongated shaft.